This staff report and recommendation is in response to petitionsfrom several heavy-duty engine manufacturers requesting the AirResources Board to extend the 1980 heavy-duty engine emissionstandards to include 1983. The additional year is needed toprevent a conflict with the new federal heavy-duty engineemission regulations promulgated on January 21, 1980, by theEnvironmental Protection Agency. The federal regulations are tobe implemented beginning in 1984.

The current California and federal standards are based upon the"9 mode" (gasoline engines) and "13 mode" (diesel engines) testprocedures which are both steady-state methods of measuringexhaust emissions. The new 1984 federal heavy-duty testprocedures, however, are based upon transient driving cycleswhich are more representative of the on road heavy-duty truckusage than the current steady-state procedures. The heavy-dutyengine transient cycle test is performed utilizing programmableelectric engine dynamometers rather than the vehicle chassis typedynamometers used for light-duty vehicle emission testing. Separate transient test cycles have been developed for gasolineand diesel engines.

As a result of these new federal regulations, the industry is inthe process of purchasing the necessary analytical equipment andmodifying test facilities to accommodate the new transienttesting requirements. This creates a problem since facilitieschangeover will be concurrent with the 1983 Californiacertification activities. A decision by manufacturers to delayfacilities conversion would not provide sufficient lead time formeeting the 1984 federal requirements. The one year extension ofthe 1980 emission standards will avert this conflict and avoid anunnecessary one year recertification; 1983 on the 9-mode or 13-mode test procedures and again a year later for 1984, assumingthe transient test procedures are eventually adopted forCalifornia.

Several manufacturers have also requested that California adoptthe federal heavy-duty test procedures and standards beginningwith 1984. It has been the Board's policy to adopt allsubstantial changes to the federal emission test procedures inorder to provide programmatic consistency between the twoagencies for the industry. At the present time, it is prematurefor the Board to consider changing California's heavy-duty engineprogram for 1984 and beyond. However, the staff is developing aproposal for the Board to consider adopting the new federalhydrocarbon and carbon monoxide standards for 1984 and subsequentmodel years along with the transient test procedures. The 1980California NOx level of control (standard adjusted for transientcycle) would be extended through 1984.

The staff will also propose that the Board adopt the new federalNOx standard for 1985 assuming EPA promulgates the final rule asscheduled. If EPA falls behind in its time schedule due tolitigation or administrative delays, the ARB will propose aCalifornia NOx standard for 1985. In no case shall the NOxstandard be less stringent than the currently adopted 1983California NOx standard. The staff is closely monitoringdevelopments on the federal level and expects to go before theBoard with the 1984 and subsequent model year proposal by earlyfall 1980.

This proposal, therefore, deals only with a recommendation tocarryover the 1980 heavy-duty engine emission standards toinclude the 1983 model year engines. These standards are 1.0gram per brake-horsepower-hour hydrocarbons (1.0 HC), 25 gramsper brake-horsepower of carbonmonoxide (25 CO), and a combinedstandard of 6.0 grams per brake-horsepower-hour of hydrocarbonsand oxides of nitrogen (6.0 HC + NOx), or optionally, standardsof 25 CO and 5.0 HC + NOx. These standards are applicable to thecurrent steady-state test procedures.